变偏移距VSP方法与效果——N35井实例的研究

VARIABLE OFFSET WVSP METHOD AND ITS EFFECTIVENESS—A CASE STUDY OF WELL N35

1. 胜利石油管理局物探公司;2. 青岛海洋大学地质系

1. Geophysical corporation, Shengli Petroleum administrative bureau;2. geology department, Ocean University of QingDao

变偏移距VSP方法是一种特殊的VSP观测方法,即WVSP方法。检波点深度与最大偏移距如何合理组合,应从最大勘探范围、允许的最大入射角和动校正拉伸三方面综合分析确定。WVSP的波场十分复杂,可把记录道集分为小偏移距道集和大偏移距道集两部分分别进行处理,其中利用接应点地震道,用二道递归滤波的方法对小偏移距道集进行波场分离。 本文以N35井为例,论述了WVSP的采集方法和处理方法。处理结果与零偏移距走廊叠加剖面和过井的高分辩率剖面有很好的一致性,在确定储集层边界方面效果很好。

WVSP is a special observation approach. To select the reasonable combination of geophone depths with maximum offsets.thc maximum investigative scalc.thc allowable maximum incident, and the stretchability due to NMO must be taken into account. WVSP wavefields are very complicated, it is thus necessary to categorize them into a near offset gather and a far offset gather and the processing on them is carried out separately.The near offset gather is Wavefield-separated by means of two-trace filtering in which an auxiliary trace is employed.The process of the WVSP method for acquistition and processing are detailed in this paper via its application to the data from Well N35. The reaults showed good consistentancy with the zero-offset corridor stacked section and the high resolution crossholc section and the adaptability in determining reservoir boundary as well.